JP4526794B2 - Acrylic resin plate manufacturing method, transparent electrode plate for touch panel, and touch panel - Google Patents

Description

  The present invention relates to a method for producing an acrylic resin plate excellent in heat resistance, a transparent electrode plate for a touch panel having a transparent substrate excellent in heat resistance, transparency, and conductive film adhesion, and a touch panel having the transparent electrode plate About.

<Acrylic resin plate>
Acrylic resin plates are used in lenses, automobile parts, lighting parts, various electronic displays and the like because of their excellent optical properties. However, the acrylic resin plate has a drawback that its heat resistance is insufficient when heat treatment is performed at a high temperature.

  As a technique for improving the heat resistance of an acrylic resin plate, there is a method of introducing a crosslinked structure by adding a polyfunctional monomer during polymerization of methyl methacrylate. For example, for the purpose of mainly improving heat resistance and impact resistance, cast polymerization is performed by adding a polyfunctional (meth) acrylate of alkylene glycol to a composition comprising a methyl methacrylate homopolymer and methyl methacrylate. A method has been proposed (see, for example, Patent Document 1). However, this method usually does not provide sufficient heat resistance. In order to obtain sufficient heat resistance by this method, it is necessary to add a large amount of polyfunctional (meth) acrylate, and in that case, the appearance of the resulting resin molded product tends to deteriorate.

  In addition, for the purpose of improving heat resistance and appearance, a method in which at least one of cyclohexadiene and a derivative thereof and a terpenoid compound and a derivative thereof is added to methyl methacrylate and a polyfunctional (meth) acrylate to perform polymerization polymerization. Has been proposed (see, for example, Patent Document 2). However, this method usually does not provide sufficient heat resistance. Further, the obtained resin plate is a resin plate that easily absorbs moisture.

  In addition, for the purpose of improving heat resistance and appearance, a composition comprising an alkyl methacrylate syrup obtained by blending an alkyl methacrylate monomer and a (meth) acrylate crosslinking agent and polymerizing a part thereof, and a crosslinking agent Has been proposed (see, for example, Patent Document 3). However, in this method, gelation tends to occur when a syrup is prepared by blending a crosslinking agent.

  In addition, for the purpose of improving the appearance, a method has been proposed in which the ratio between the crosslinking agent and the alkyl methacrylate polymer is defined in a certain region (see, for example, Patent Document 4). However, here, there is no description of implementation in which the polyfunctional monomer exceeds 20% by mass, and this method usually cannot provide sufficient heat resistance. Furthermore, in order to obtain a resin plate having high heat resistance and excellent appearance, there are restrictions on the composition, which becomes a hindrance to industrialization.

  In addition, a monomer mainly composed of methyl methacrylate and allyl (meth) acrylate are at least two kinds having a difference of 5 ° C. or more between a high and low 10-hour half-life temperature of 75 ° C. A method for producing an acrylic resin plate that undergoes cast polymerization using a radical polymerization initiator has been proposed (see, for example, Patent Document 5). However, in this method, the polymerizability of the allyl group is poor and sufficient heat resistance tends not to be obtained.

  Furthermore, a method for producing an optical material that undergoes radical polymerization based on a polyfunctional (meth) acrylate having an olefinic group as a main component has been proposed (for example, see Patent Document 6). However, this method has a problem that the plate is cracked unless it is peeled off at a high temperature in the peeling step during production.

<Transparent electrode plate for touch panel and touch panel>
A display device-integrated input device in which a transparent touch panel is arranged on a display device such as a liquid crystal display or a cathode ray tube touches the display screen with an input pen or a finger, so that the touch panel acts as an input device to facilitate an input operation. Therefore, it is used as an operation screen of an automatic teller machine such as a portable information terminal or a bank. In particular, a resistive film type analog touch panel is most widely used because it can be applied to any operation screen.

  A resistance film type analog touch panel generally includes an upper transparent electrode plate and a lower transparent electrode plate, and the upper and lower transparent electrode plates have a transparent substrate and a transparent conductive film formed on the transparent substrate. It is an electrode plate, and the upper and lower transparent electrode plates have a configuration in which the transparent conductive films are arranged so as to face each other.

  When the upper transparent electrode plate of the touch panel having such a configuration is pressed with an input pen or a finger, the upper transparent electrode plate is bent and the transparent conductive films of the upper and lower transparent electrode plates are in contact with each other at the pressing point. And the coordinate of this contact point is detected by the measurement of electrical resistance, and input information is read.

  As a transparent electrode plate of such a touch panel, a resin plate is generally used as an upper transparent electrode plate, and a glass plate or a resin plate is used as a transparent substrate for a lower transparent electrode plate, and vacuum deposition is performed on the surface of these transparent substrates. A method in which a transparent conductive film is formed by a vacuum film formation method such as a sputtering method, a CVD (chemical vapor deposition) method, or an ion plating method has been used.

  However, the lower electrode plate using a glass plate as a transparent substrate is prone to cracking when assembling and transporting the touch panel, or pressing with a pen or hand, making it difficult to reduce the thickness, making it difficult to reduce the weight, etc. There's a problem.

  On the other hand, when a resin plate is used as a transparent substrate, the problems of substrate breakage, thickness reduction, and weight reduction that occur when a glass plate is used as a transparent substrate can be easily solved. Actually, various studies have been made on upper and lower electrode plates using a resin plate as a transparent substrate (see, for example, Patent Documents 7, 8, and 9). However, the transparent substrate using a resin plate such as polyethylene terephthalate resin disclosed in Patent Documents 7, 8, and 9 has insufficient transparency. In addition, since the heat resistance is insufficient, the transparent substrate surface is easily deformed easily when a transparent conductive film is formed on the transparent substrate. The adhesion of the transparent conductive film is low and the durability is insufficient. There is a problem that further processing is required.

Further, a methacrylic resin molding material obtained by polymerizing methyl methacrylate and neopentyl glycol dimethacrylate, which is a polyfunctional (meth) acrylate, as monomers is disclosed (for example, see Patent Document 10). However, here, it is not disclosed at all that this methacrylic resin molding material can be used as a transparent substrate of a transparent electrode plate for a touch panel, and it is not suggested at all what composition is suitable as a transparent electrode plate for a touch panel. . Furthermore, since the methacrylic resin molding material described in Patent Document 10 has a low polymerization rate of 4 to 62% by mass, the polymerization rate is further increased by a process such as compression molding or extrusion molding when the molding material is used as a product. It needs to be high. For this reason, distortion occurs and it is not suitable for use on a touch panel.
Japanese Patent Publication No. 4-75241 JP 2002-265538 A JP 63-30510 A JP-A-61-225207 Japanese Patent Laid-Open No. 9-25305 Japanese Examined Patent Publication No. 4-30410 JP 2000-276301 A JP 2001-14951 A JP 2001-34418 A Japanese Patent Publication No. 5-6570

  The objective of this invention is providing the manufacturing method of the acrylic resin board which was excellent in the board crack prevention property in the peeling process at the time of manufacture, and excellent in heat resistance. Furthermore, the objective of this invention is providing the transparent electrode plate for touchscreens which has the resin substrate excellent in heat resistance, transparency, and thin film adhesiveness, and the touchscreen which has this transparent electrode plate.

The present invention relates to a monoethylenically unsaturated monomer (5 to 65% by mass) containing a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms, and a polyfunctional (meth) acrylate represented by the following general formula (1). Containing 0.001 to 1 part by weight of a polymerization initiator having a 10 hour half-life temperature of 80 ° C. or more and 0.015 to 0.2 part by weight of terpinolene per 100 parts by weight of a mixture containing 35 to 95% by weight This is a method for producing an acrylic resin plate having a step of polymerizing and curing the polymerizable mixture.

(Wherein R ¹ represents H or CH ₃ ).

Furthermore, the present invention is an acrylic resin laminate in which a tin-added indium oxide film is formed on at least one surface of an acrylic resin plate obtained by the above production method.

  Furthermore, this invention is a transparent electrode plate for touch panels which has the said acrylic resin laminated body.

The invention further includes an upper transparent electrode plate and the lower transparent electrode plates, the upper transparent electrode plate and said lower transparent electrode plates were formed on at least one surface of the transparent substrate and the transparent substrate indium tin oxide A transparent electrode plate having a film, wherein the upper transparent electrode plate and the lower transparent electrode plate are arranged such that the tin-added indium oxide films face each other, the upper transparent electrode At least one of the plate and the lower transparent electrode plate is the touch panel transparent electrode plate.

In the method for producing an acrylic resin plate of the present invention, a specific composition is adopted, so that the excellent optical properties of the acrylic resin are maintained, and further, heat resistance, appearance, and cracking in the peeling process during production. The prevention can be greatly improved. An acrylic resin laminate formed by forming an ITO film (tin-added indium oxide film) on the acrylic resin plate is very useful as a transparent electrode plate for a touch panel.

  The transparent electrode plate for a touch panel of the present invention has heat resistance that can withstand an inorganic thin film forming process and an electrode thermosetting process while maintaining the excellent optical properties inherent in acrylic resins, and has extremely thin film adhesion. Since it is excellent, the surface treatment of the resin substrate is not required. Furthermore, because the resin plate can be used for the substrate of the transparent electrode plate for the touch panel, it is possible to easily prevent damage to the touch panel, to reduce the weight, and to reduce the wall thickness. Application to shapes is possible.

<Acrylic resin plate>
The method for producing an acrylic resin plate according to the present invention includes 5 to 65% by mass of a monoethylenically unsaturated monomer containing a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms, and the general formula (1). 0.001 to 1 part by weight of a polymerization initiator having a 10-hour half-life temperature of 80 ° C. or more per 100 parts by weight of a mixture containing 35 to 95% by weight of the polyfunctional (meth) acrylate shown, and terpinolene 0.015 to 0 .2 parts by mass to form a polymerizable mixture, and a method for producing an acrylic resin plate comprising a step of polymerizing and curing the polymerizable mixture.

  Content of the monoethylenically unsaturated monomer containing the methacrylic acid alkyl ester which has a C1-C4 alkyl group is 5-65 mass% in a mixture. When the content is 5% by mass or more, the appearance is improved, and when it is 65% by mass or less, the heat resistance tends to be improved. Further, the content is preferably 10 to 55% by mass, and more preferably 15 to 50% by mass. Moreover, when the total amount of the monoethylenically unsaturated monomer containing the methacrylic acid alkyl ester which has a C1-C4 alkyl group is 100 mass parts, the methacrylic acid alkyl ester which has a C1-C4 alkyl group Is preferably 50 parts by mass or more, and the ratio of other monoethylenically unsaturated monomers is preferably 50 parts by mass or less. When the ratio is set, transparency tends to be improved, and heat resistance may be further improved.

  Examples of the alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, and methacrylic acid. Examples include t-butyl acid. These can also be used in combination. Of these, methyl methacrylate is particularly preferred.

  Examples of monoethylenically unsaturated monomers other than methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms include, for example, styrene, α-methylstyrene, acrylonitrile, acrylic acid, methacrylic acid, methyl acrylate, acrylic acid Ethyl, n-butyl acrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, isostearyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, isobornyl methacrylate, glycidyl methacrylate, tetrahydro methacrylate Examples include furfuryl, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, and the like. These can also be used in combination. Among them, alkyl methacrylate having an alkyl group having 8 to 20 carbon atoms such as 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, and isostearyl methacrylate is preferable from the viewpoint of a decrease in water absorption.

  Content of polyfunctional (meth) acrylate shown by following General formula (1) is 35-95 mass% in a mixture. When this content is 35% by mass or more, the heat resistance is improved, and when it is 95% by mass or less, the appearance tends to be good. This content is preferably 45 to 90% by mass, and more preferably 50 to 85% by mass.

(Wherein R ¹ represents H or CH ₃ ).

The compound represented by the general formula (1), for example, bis (oxymethyl) tricyclo [5,2,1,0 ^2,6] decane acrylate, bis (oxymethyl) tricyclo [5, 2, 1, 0 ^2,6 ] decanedimethacrylate. These can also be used in combination.

In the present invention, 0.001 to 1 part by mass of a polymerization initiator having a 10 hour half-life temperature of 80 ° C. or more and 100 parts by mass of terpinolene per 100 parts by mass of the above-mentioned monomer as a main component .2 parts by mass to make a polymerizable mixture.

  Examples of the polymerization initiator having a 10-hour half-life temperature of 80 ° C. or more include 1,1′-azobis (cyclohexane-1-carbonitrile) (10-hour half-life temperature 88 ° C.), 2,2′-azobis (2 , 4,4-trimethylpentene) (10-hour half-life temperature 110 ° C.), 2-cyano-2-propyrazoformamide (10-hour half-life temperature 104 ° C.), dicumyl peroxide (10-hour half-life temperature 117 ° C.) T-butylcumyl peroxide (10-hour half-life temperature 121 ° C.), di-t-butyl peroxide (10-hour half-life temperature 126 ° C.), t-butyl peroxy-3,3,5-trimethylhexanoate (10-hour half-life temperature 100 ° C.), t-butyl peroxylaurate (10-hour half-life temperature 95 ° C.), t-butyl peroxyacetate (10-hour half-life temperature 03 ° C.), di-t-butylperoxyhexahydroterephthalate (10-hour half-life temperature 83 ° C.), di-t-butyl peroxyazelate (10-hour half-life temperature 99 ° C.), t-butyl peroxyallyl carbonate (10-hour half-life temperature 94 ° C), t-butyl peroxyisopropyl carbonate (10-hour half-life temperature 97 ° C), 1,1-di-t-butylperoxycyclohexane (10-hour half-life temperature 97 ° C), t -Hexylperoxyisopropyl monocarbonate (10 hour half-life temperature 95 ° C), 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane (10 hour half-life temperature 95 ° C), 1,1- And di-t-hexylperoxy-3,3,5-trimethylcyclohexane (10 hour half-life temperature 87 ° C.). These can also be used in combination. The upper limit of the 10-hour half-life temperature is preferably 130 ° C.

The addition amount of the polymerization initiator having a 10-hour half-life temperature of 80 ° C. or more is 0.001 to 1 part by mass per 100 parts by mass of the mixture. When this addition amount is 0.001 part by mass or more, heat resistance tends to be improved even if terpinolene is added. Moreover, there exists a tendency for a residual initiator to reduce that it is 1 mass part or less, and for heat stability to become favorable. Furthermore, this addition amount is preferably 0.005 to 0.5 parts by mass.

  A polymerization initiator having a 10-hour half-life temperature of less than 80 ° C. can be used in combination with such a polymerization initiator. Examples of the polymerization initiator having a 10-hour half-life temperature of less than 80 ° C. include t-butyl peroxyisobutyrate (10-hour half-life temperature 77 ° C.), t-butyl peroxy-2-ethylhexanoate (10 Time half-life temperature 72 ° C), t-butyl peroxypivalate (10-hour half-life temperature 55 ° C), t-hexyl peroxypivalate (10-hour half-life temperature 53 ° C), t-butylperoxyneodecano Ate (10-hour half-life temperature 47 ° C.), 2,2′-azobisisobutyronitrile (10-hour half-life temperature 65 ° C.), 2,2′-azobis (2,4-dimethylvaleronitrile) (10 hours And a 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile) (10 hour half-life temperature 30 ° C.). These can also be used in combination.

Terpinolene is a component that functions as a polymerization regulator. Hereinafter, this is referred to as “compound (a)” .

  The amount of compound (a) added is 0.015 to 0.2 parts by mass per 100 parts by mass of the mixture. If this addition amount is 0.015 parts by mass or more, it is difficult to break the plate in the peeling step during production, and if it is 0.2 parts by mass or less, the residual monomer tends to decrease and the thermal stability tends to be good. Here, the peeling process at the time of production is a process from the end of polymerization and curing until the acrylic resin plate is peeled from the mold. Furthermore, this addition amount is preferably 0.02 to 0.15 parts by mass.

  An acrylic resin plate can be obtained by polymerizing and curing the polymerizable mixture described above. Various conventionally known methods can be used as a polymerization and curing method for the polymerizable mixture. Particularly preferred is a so-called casting polymerization method in which a polymerizable mixture is injected into a mold, polymerized and cured, and then peeled off from the mold. Below, the method of the casting polymerization which uses methyl methacrylate as a methacrylic acid alkylester which has a C1-C4 alkyl group is illustrated. However, the present invention is not limited to this.

First, methyl methacrylate, bis (oxymethyl) tricyclo [5,2,1,0 ^2,6] Dekanji (meth) acrylate, further depending on other copolymerizable necessary monoethylenically unsaturated monomers Charge into a suction bottle and stir to make a mixture. A polymerization initiator and a polymerization regulator [compound (a)] are added to the mixture, and vacuum degassing is performed to obtain a polymerizable mixture. This polymerizable mixture is poured into a mold constituted by sandwiching a gasket between a pair of tempered glass sheets, placed in a heating furnace and polymerized and cured at 40 to 70 ° C. for 2 to 5 hours, and at 100 to 150 ° C. for 1 to 6 hours. And peeling from the mold to obtain an acrylic resin plate.

  Instead of this tempered glass sheet, for example, a mirror surface SUS sheet, a glass sheet with fine irregularities on the surface, or an endless belt made of mirror surface SUS that runs oppositely can be used as a mold. Further, the polymerization temperature and time may be appropriately selected as desired.

  The thickness of the acrylic resin plate is preferably 0.5 to 5 mm. When the plate thickness is 0.5 mm or more, when the plate is produced by bulk polymerization, cracks tend not to occur when the acrylic resin plate is peeled from the mold. Moreover, when it is 5 mm or less, there is a tendency that it is difficult to break the plate during polymerization.

  The acrylic resin plate obtained in the present invention is greatly improved in heat resistance, appearance, and plate crack prevention in the peeling process during production while maintaining the excellent optical properties of the acrylic resin. Such acrylic resin plates are, for example, peripheral materials for exothermic light sources such as incandescent lamp covers and halogen lamp covers, parts of heating household appliances such as clothes dryers, microwave ovens, ovens, eyeglass lenses, sunglasses lenses, and cameras. In-vehicle materials such as lenses, video camera lenses, goggles lenses, contact lenses and other optical lenses, meter covers and other in-vehicle parts, in-vehicle audio equipment parts, in-vehicle display device parts, in-vehicle navigation system parts, Furthermore, it can be used for various display members such as a front plate of various display devices such as a plasma display device, a liquid crystal display device, and a projection display device, and a light guide plate of a liquid crystal display.

  The polymerizable mixture contains the above-described components as main components, but if necessary, a colorant, a release agent, an antioxidant, a stabilizer, an antistatic agent, an antibacterial agent, a flame retardant, and an impact resistance modifier. A quality agent, a light stabilizer, an ultraviolet absorber, a light diffusing agent, a polymerization inhibitor, a chain transfer agent, and the like can be added.

< ITO (tin-added indium oxide) film>
The acrylic resin plate obtained in the present invention can be formed into an acrylic resin laminate by forming a tin-added indium oxide film on at least one surface thereof. The indium tin oxide film, Ru film Der transparent and conductive.

In the following description, an ITO (tin-added indium oxide) film is appropriately referred to as a “transparent conductive film” .

An acrylic resin laminate in which an ITO film is formed on at least one surface of an acrylic resin plate can be used for a transparent conductive material. For example, electrical component circuit materials such as capacitors and resistors, copying materials such as electrophotography and electrostatic recording, transparent electrodes for signal input for liquid crystal displays, electrochromic displays, electroluminescence displays, touch panels, etc. In addition to photoelectric conversion elements such as batteries and optical amplifiers, it can be used for various applications such as antistatic members, electromagnetic wave shielding members, surface heating elements, and sensors. Especially, it is preferable to utilize as a transparent electrode plate for touch panels.

<Transparent electrode plate for touch panel>
The transparent electrode plate for touch panels of this invention has the acrylic resin board obtained by this invention as a transparent substrate, and the transparent conductive film formed on at least one surface of this acrylic resin board. As a method for forming a transparent conductive film on an acrylic resin plate, various conventionally known film forming methods can be used. Examples of film forming methods include vacuum film forming methods such as vacuum deposition, sputtering, CVD, and ion plating. Here, a specific example of film formation by sputtering of an ITO thin film will be described. First, in the cleaning step, the transparent substrate is washed with pure water or alkaline water, and dried in the atmosphere at a temperature of 120 ° C. or higher, preferably 120 to 130 ° C. for 1 to 4 hours. And the sputtering process of ITO is performed in the temperature of 100-140 degreeC under a vacuum, Preferably it is 120 degreeC. Thereafter, the electrode and the lead electrode are applied with a silver paste and cured at a temperature of 130 to 170 ° C., preferably 150 ° C.

  The transparent electrode plate for a touch panel preferably has a deflection temperature under load of 150 ° C. or higher. If the deflection temperature under load is 150 ° C. or higher, the resin substrate tends to be difficult to deform when the silver paste is cured. The deflection temperature under load of the transparent electrode plate is the same as the deflection temperature under load of the acrylic resin plate constituting the transparent electrode plate when the thickness of the transparent conductive film is as thin as 1 μm or less. Therefore, in this case, the deflection temperature under load of the acrylic resin plate may be measured and used as the deflection temperature under load of the transparent electrode plate.

  0.5-2 mm is preferable and, as for the thickness of the acrylic resin board used for the transparent electrode plate for touchscreens, 0.5-1 mm is more preferable. Moreover, 10-50 nm is preferable and, as for the thickness of a transparent conductive film, 25-40 nm is more preferable. If the thickness within these ranges is adopted, it is possible to reduce the weight and thickness as compared with the transparent electrode plate for a touch panel using a glass substrate.

  The acrylic resin plate used for the transparent electrode plate for a touch panel is preferably uncolored. Further, an antireflection film can be formed on the side without the transparent conductive film. When the thickness of the transparent electrode plate for a touch panel is 1 mm, the total light transmittance is a value based on the total light transmittance measurement method shown in JIS-K7361, and is preferably 91% or more. If the total light transmittance is 91% or more, sufficient transparency as a transparent electrode plate for a touch panel can be obtained.

<Touch panel>
The touch panel of the present invention comprises an upper transparent electrode plate and a lower transparent electrode plate, and the upper transparent electrode plate and the lower transparent electrode plate are formed on a transparent substrate and at least one surface of the transparent substrate. A transparent electrode plate having a film, wherein the upper transparent electrode plate and the lower transparent electrode plate are arranged so as to face each other so that the transparent conductive films face each other. And at least one of this lower transparent electrode plate is the transparent electrode plate for touchscreens of this invention, It is characterized by the above-mentioned.

  Hereinafter, the suitable example of the transparent electrode plate for touchscreens of this invention and a touchscreen using the same is demonstrated using FIGS. 1-3. FIG. 1 is a schematic sectional view showing an example of the transparent electrode plate for a touch panel of the present invention, and FIG. 2 is a schematic plan view thereof. FIG. 3 is a schematic cross-sectional view showing an example of a touch panel using the transparent electrode plate shown in FIGS. 1 and 2 as a lower transparent electrode plate.

  The touch panel shown in FIG. 3 has a structure in which a lower transparent electrode plate 1 and an upper transparent electrode plate 7 are arranged to face each other with a spacer 6 therebetween. As shown in FIGS. 1 and 2, the lower transparent electrode plate 1 includes a transparent substrate 2, a transparent conductive film 3 formed on one surface of the transparent substrate 2, and an end portion on the transparent conductive film 3. The electrode 4 is connected to the electrode 4, and the lead electrode 5 is connected to the electrode 4. The upper transparent electrode plate 7 has the same structure as the lower transparent electrode plate 1. That is, the upper transparent electrode plate 7 similarly has a transparent substrate 8, a transparent conductive film 9, an electrode 10, and the like.

  The lower transparent electrode plate 1 and the upper transparent electrode plate 7 have the transparent conductive films 3 and 9 inside, a dot spacer 11 interposed between the transparent electrode plates 1 and 7, and the electrodes 4 and 10. It arrange | positions through the spacer 6 at fixed intervals so that a direction may cross | intersect. When the touch panel having such a configuration is pressed from above the upper transparent electrode plate 7 with a pen or a finger, the upper transparent electrode plate 7 is deformed and the lower transparent conductive film 3 and the upper transparent conductive film 9 are brought into contact conduction. The input is complete.

  Since the transparent electrode plate for a touch panel of the present invention has high transparency and high rigidity, it is preferably used as the lower transparent electrode plate 1. 1 to 3 show such an example. However, the present invention is not limited to this. For example, the transparent electrode plate for a touch panel of the present invention may be used as the upper transparent electrode plate 7 or may be used for both the lower transparent electrode plate 1 and the upper transparent electrode plate 7.

  Hereinafter, the present invention will be described more specifically with reference to examples. In the following description, “part” is based on mass. Each evaluation in the table was performed according to the following method.

(1) Evaluation of acrylic resin plate:
(1-1) Deflection temperature under load:
In order to evaluate the heat resistance of the acrylic resin plate, the deflection temperature under load was measured according to the measurement method shown in JIS-K7207.

(1-2) Haze:
In order to evaluate the optical characteristics of the acrylic resin plate, haze was measured in accordance with the measurement method shown in JIS-K7136.

(1-3) Plate crack prevention:
In order to evaluate the acrylic resin plate, 10 samples were prepared, and after the polymerization and curing were completed, the mold was cooled to 40 ° C. or lower, and the plate was not cracked until the acrylic resin plate was peeled off from the mold. The number of samples is indicated by n / 10.

(1-4) Appearance:
In order to evaluate the appearance of the acrylic resin plate, ten samples were prepared, and the number of samples free from defects such as whitening and sink marks was visually indicated by n / 10.

(2) Evaluation of transparent electrode plate for touch panel:
(2-1) Total light transmittance:
In order to evaluate the transparency of the transparent electrode plate for a touch panel, the total light transmittance was measured according to the measurement method shown in JIS-K7361.

(2-2) Deformation of substrate:
For a series of touch panels, whether or not the acrylic resin plate (substrate) is deformed, drying the substrate before forming the transparent conductive film (ITO), then forming the film by sputtering, and applying and curing the silver paste after forming the film The transparent electrode plate was observed with the naked eye, and when the acrylic resin plate was not deformed, it was evaluated as “◯” (good), and when it was deformed, it was evaluated as “x” (bad).

(2-3) ITO state:
The state of the transparent conductive film (ITO) was observed in a series of manufacturing processes for transparent electrode plates for touch panels such as film formation by sputtering and silver paste coating and curing after film formation, and optical distortion and cracks were observed. When it was not, it was evaluated as “◯” (good), and when optical distortion or crack was observed, it was evaluated as “x” (bad).

(2-4) Adhesiveness:
Using a cutter, scratches were made on the transparent conductive film of the transparent electrode plate for touch panels in a grid pattern of 11 pieces vertically and horizontally at intervals of 1 mm so as to reach the resin substrate, and 100 squares of 1 × 1 mm were produced. . Adhesive tape (manufactured by Nichiban Co., Ltd., cellophane tape) was closely adhered on the mesh, and was peeled off rapidly by 45 °. At this time, the number (n) of the cells remaining without peeling off the transparent conductive film was indicated as n / 100. Specifically, the value of n is preferably 96 or more, more preferably 100. It can be said that the larger the value of n, the higher the adhesiveness of the transparent conductive film, and the better the transparent electrode plate for touch panel.

[Example 1]
And 20 parts of methyl methacrylate, bis (oxymethyl) tricyclo [5,2,1,0 ^2,6] per 100 parts of a mixture of a decane dimethacrylate 80 parts, as a polymerization initiator 2,2'-azobis (2, 4-dimethyl-4-methoxyvaleronitrile) 0.05 part, 0.05 part of t-hexylperoxypivalate, 0.05 part of t-hexylperoxyisopropyl monocarbonate, 0.03 part of terpinolene are mixed and suctioned. The mixture was charged into a bottle and stirred, and vacuum deaeration was performed to obtain a polymerizable mixture.

  This polymerizable mixture was poured into a mold formed by sandwiching a gasket between a pair of tempered glass sheets having a distance of 1.7 mm, removed from the bubbles, placed in a heating furnace, and heated at 55 ° C. for 1 hour and at 50 ° C. for 1 hour. Subsequently, polymerization was carried out at 135 ° C. for 3 hours. Thereafter, the mold was cooled to 40 ° C. or lower and peeled to obtain an acrylic resin plate having a thickness of 1 mm.

  The resin plate was not cracked during cooling after polymerization and curing, and no plate cracking occurred when it was peeled off. Further, this resin plate had a good appearance without whitening or sinking. The haze of the resin plate was measured and found to be 0.2%, indicating good transparency. Further, the deflection temperature under load exceeded 200 ° C. Table 1 shows the main raw material composition and evaluation results of the polymerizable mixture of this example.

[Examples 2 to 9, Comparative Examples 1 to 5]
An acrylic resin plate was produced in the same manner as in Example 1 except that the raw material compositions shown in Tables 1 to 3 were adopted. The evaluation results are shown in Tables 1-3.

<Deposition of transparent conductive film>
Each acrylic resin plate obtained in Examples 1 to 9 and Comparative Examples 1 to 5 was washed with pure water, placed in a hot air drying furnace, and dried in air at 120 ° C. for 2 hours. Next, ITO was formed as a transparent conductive film on the resin plate by sputtering to obtain an acrylic resin laminate. The film thickness of the transparent conductive film was adjusted to about 30 nm. Moreover, in this sputtering, In ₂ O ₃ / SnO ₂ having a mass ratio of 95/5 is used as a target, exhausted to 10 ⁻³ Pa, argon / oxygen having a volume ratio of 92.5 / 7.5 is used as an introduction gas, RF sputtering was performed under heating at 120 ° C.

<Manufacture of transparent electrode plate for touch panel>
Each of the acrylic resin laminates is cut into a width of 250 mm and a length of 180 mm, and a silver paste is applied thereto in a predetermined pattern and cured at 150 ° C. to form an electrode and a lead electrode. The configuration shown in FIGS. 1 and 2 Each of the transparent electrode plates for touch panels was manufactured. The film thickness of this electrode and the lead electrode was adjusted to about 10 μm. The evaluation result of each obtained transparent electrode plate for touch panels is shown in Tables 1-3.

<Touch panel>
Each of the touch panel transparent electrode plates was used as the lower transparent electrode plate 1 to fabricate touch panels having the configuration shown in FIG. Specifically, each of the transparent electrode plates for a touch panel was used as the lower transparent electrode plate 1. As the upper transparent electrode plate 7, an ITO film having a film thickness of about 25 nm is formed on a 188 μm thick polyethylene terephthalate film (product name: Tetron film, manufactured by Teijin Ltd.) in the same manner as the lower transparent electrode plate. What was done was used. As the spacer 6, a double-sided tape having a thickness of 100 μm was used.

  Further, the lower transparent conductive film 3 is coated with a photocurable acrylic resin in a predetermined pattern and cured by irradiating with ultraviolet rays, whereby dot spacers 11 having a height of 10 μm and a diameter of 50 μm are staggered at a pitch of 3 mm. It was formed so that it might be arranged in. Further, an insulating film (not shown) was formed on the electrode 4 and the electrode 10. Then, by assembling a structure in which the lower transparent electrode plate 1 and the upper transparent electrode plate 7 are arranged to face each other with a spacer 6 therebetween, a touch panel having a size corresponding to 12 types, that is, 250 mm wide × 180 mm long is manufactured. did.

The abbreviations in each table indicate the following compounds.
"ADMVN": 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile) (10 hour half-temperature 30 ° C)
"HPP": t-hexyl peroxypivalate (10 hour half-temperature 53 ° C)
"HPIC": t-hexylperoxyisopropyl monocarbonate (10 hour half-life temperature 95 ° C)
"BPIC": t-butyl peroxyisopropyl carbonate (10 hour half-life temperature 97 ° C)
· "TDMA": bis (oxymethyl) tricyclo [5,2,1,0 ^2,6] decane dimethacrylate - "ISMA": isostearyl methacrylate "TP": terpinolene.

  As shown in Table 1 and Table 2, in Examples 1 to 9, good results with respect to heat resistance, transparency, plate cracking prevention, transparency, appearance, and adhesion of the transparent electrode plate for touch panel of the acrylic resin plate was gotten. The touch panel also worked properly.

  On the other hand, as shown in Table 3, in Comparative Examples 1 to 3, problems such as plate cracking occurred in the peeling step of the acrylic resin plate. Further, in Comparative Examples 4 and 5, the acrylic resin plate had low heat resistance and was deformed when heated at 150 ° C. during electrode formation, which was unsuitable for a touch panel.

It is typical sectional drawing which shows an example of the transparent electrode plate for touchscreens of this invention. It is a schematic plan view which shows an example of the transparent electrode plate for touchscreens of this invention. It is typical sectional drawing which shows an example of the touchscreen which uses the transparent electrode plate shown in FIG. 1 and FIG. 2 as a lower transparent electrode plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower transparent electrode plate 2 Transparent substrate 3 Transparent conductive film 4 Electrode 5 Lead electrode 6 Spacer 7 Upper transparent electrode plate 8 Transparent substrate 9 Transparent conductive film 10 Electrode 11 Dot spacer

Claims (5)

5 to 65% by mass of a monoethylenically unsaturated monomer containing a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms, and 35 to 95% by mass of a polyfunctional (meth) acrylate represented by the following general formula (1) A polymerization mixture containing 0.001 to 1 part by mass of a polymerization initiator having a 10 hour half-life temperature of 80 ° C. or more and 0.015 to 0.2 part by mass of terpinolene per 100 parts by mass of a mixture containing And a method for producing an acrylic resin plate, comprising a step of polymerizing and curing the polymerizable mixture.

(In the formula, R ¹ represents H or CH _3. ) An acrylic resin laminate obtained by forming a tin-added indium oxide film on at least one surface of an acrylic resin plate obtained by the production method according to claim 1. Transparent electrode plate for a touch panel having an acrylic resin laminate according to claim 2 Symbol placement. The transparent electrode plate for a touch panel according to claim 3 , wherein the deflection temperature under load is 150 ° C or higher. An upper transparent electrode plate and a lower transparent electrode plate, the upper transparent electrode plate and the lower transparent electrode plate having a transparent substrate and a tin-added indium oxide film formed on at least one surface of the transparent substrate A touch panel in which the upper transparent electrode plate and the lower transparent electrode plate are arranged so that the tin-added indium oxide films face each other, the upper transparent electrode plate and the lower transparent electrode plate The touch panel in which at least one of the electrode plates is the transparent electrode plate for a touch panel according to claim 3 or 4 .

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